Gau Ban is a boy striving to become a "Sevalle," the most powerful warrior class in the mercenary kingdom of Guruda. His older sister, Elle Rag, is the 59th "Sevalle" and bears the prestigious title of "Shadow Skill." The narrative centers on the two siblings as they battle magical monsters and historical warriors. A significant portion of the story involves a combat style known as "Shadow Skills," which relies exclusively on hand and foot techniques. This power activates when historical warriors chant "We are invincible!" and gain superhuman abilities.